This invention relates to a vaporization burner operated by means of liquid fuel for heaters, especially motor vehicle heaters, having a combustion chamber into which combustion air can be introduced in a turbulent manner under pressure, having a vaporization body made of an absorbent material that is filled with fuel and has an essentially flat evaporation surface, for the vaporization of the supplied fuel before mixing with the combustion air, as well as having an electric ignition device for the ignition of the initial flame.
In the known vaporization burners of this type, a spiral or rod-shaped glow plug is used as the ignition device and projects laterally into the combustion chamber at a point that is located at a distance in front of the evaporation surface. Initially, the ignition device provides heat that is required to bring the fuel to its vaporization temperature. However, because of its construction, the glow plug requires a lot of space in the combustion chamber, which, as a rule, is relatively small. The glow plug, by protruding into the combustion chamber, sometimes impairs the continuing combustion process considerably, especially because it disturbs the flow in the combustion chamber. Furthermore, only a fraction of the heat energy produced by the electrical current in the ignition device is supplied to the evaporation surface. In the case of rod-shaped spark plugs, it is also difficult to reach the required surface temperature, while spiral spark plugs tend to lead to a coking of the spirals with resulting short circuits and ground fault circuits.
This invention is based on the objective of creating a vaporization burner which has an especially simple construction and results in improved efficiency, but which does not disturb the combustion in the combustion chamber.
According to preferred embodiments of the invention, this objective is achieved by the fact that an essentially flat glowing heating element is provided which is disposed in a plane that is parallel to the evaporation surface directly in front of or in the vaporization body.
On the basis of the embodiments according to the invention, the heat supply required at the start is targeted and takes place where it is needed for the generation of the initial flame; the turbulence of the fuel in the combustion chamber is virtually unimpaired; the danger of coking can be largely eliminated; and the current consumption is decreased because of the better utilization of heat.
A constructively especially simple solution can be obtained when the glowing heating element consists of a heater plug filament formed into a flat geometrical shape.
In a further development of the invention, the vaporization body and the glowing heating element are supported on a common support which expediently is detachably connected with the other parts of the burner. This not only decreases the constructive expenditures, but also permits, in an especially convenient manner, a simultaneous exchange of the vaporization body and the glowing heating element. In this case, the vaporization body and the glowing heating element can be exchanged together with the carrier.
The glowing heating element may be developed as a mechanical mounting for the vaporization body. Vice versa, the vaporization body itself may be designed as the carrier for the glowing heating element. The common support or the vaporization body itself may be developed as a removable, lid-type, front-side end of the combustion chamber. In addition to the exchange of the vaporization body and the glowing heating element, this also permits an easy cleaning of the combustion chamber. The glowing heating element may sit on the front surface of the vaporization body facing the combustion chamber or may be imbedded in open grooves provided there. Electrical connections for the glowing heating element may simply be led through the vaporization body and may be expediently formed as plug connection elements. By a distribution of the glowing heating element, for example, by using element wires with large distances between turns, essentially over the whole evaporation surface of the vaporization body, the coking danger can be reduced by a large-surface burning-away of combustion residues.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.